A study of 229 Israeli women undergoing in-vitro fertilization (IVF) to treat infertility found that a 15-minute visit from a trained "medical clown" immediately after the embryos were placed in the womb increased the chance of pregnancy to 36%, compared with 20% for women whose embryo transfer was comedy-free.

After controlling for factors such as the women's age, the nature and duration of their infertility, the number of embryos used and the day on which they were transferred into the uterus, researchers found an even greater effect of therapeutic laughter: the women who were entertained by a clown were 2.67 times more likely to get pregnant than those in the control group.

The quasi-randomized controlled study was published in one of the leading journals on infertility research, Fertility and Sterility, and led by Israeli researcher Shevach Friedler.

It is considered only quasi-randomized because the timing of the recruitment of the control group was slightly different from that of the clown group.

In the trial, the professional medical clown — who was dressed as a chef and performed the same light routine each time — visited patients during the half-hour after embryo transfer, when women typically stay lying down and allow the embryos to settle in. The idea was to help reduce women's stress, which laughter has been shown to do, and, hopefully, reap the physiological benefits.

Researchers have long known that stress can sometimes play a role in infertility. The condition not only creates stress by itself, but treatments for it can often add to the burden: during IVF, women's ovaries must be artificially stimulated to produce multiple eggs — a process that requires several drugs delivered by injection. Then, the eggs are retrieved and inseminated outside the body. After the embryos grow for three to five days, the most viable ones are placed back into the uterus.

It's possible that the more relaxed a woman is when the embryos first enter the womb, the more likely they are to nestle in and grow successfully. In previous research, a Cochrane review of studies found, potentially stress-relieving acupuncture treatments done at the time of embryo transfer have nearly doubled pregnancy rates.

Of course, with any study, there's always the possibility that the results happened just by chance. Statistically speaking, a result is accepted as significant if the probability of it occurring by chance is less than 1 in 20. The findings in the clown study were significant to the .008 level, meaning that the chances that the clown had no effect were 8 in 1,000.

Nonetheless, until the study is replicated, I remain skeptical. Either way, though, as far as treatments go, at least a clown is noninvasive, cheap and unlikely to do harm. And if it works, a lot more people struggling with infertility will have something to smile about.